diff --git a/.CI/Jenkinsfile b/.CI/Jenkinsfile
index 8d7179f85..85766d530 100644
--- a/.CI/Jenkinsfile
+++ b/.CI/Jenkinsfile
@@ -18,7 +18,7 @@ pipeline {
   stage('build') {
     agent {
       docker {
-        image 'modelicaspec/latexml:20201130'
+        image 'modelicaspec/latexml:20210330'
         label 'linux'
         alwaysPull true
       }
diff --git a/.CI/latexml/Dockerfile b/.CI/latexml/Dockerfile
index a2b9d35b8..ea3f6426d 100644
--- a/.CI/latexml/Dockerfile
+++ b/.CI/latexml/Dockerfile
@@ -23,7 +23,7 @@ RUN sed -i s,http://archive.ubuntu.com/ubuntu/,mirror://mirrors.ubuntu.com/mirro
  && $INSTALL/install-tl --profile texlive.profile \
  && rm texlive.profile \
  && tlmgr update --self --all --reinstall-forcibly-removed \
- && tlmgr install latexmk listings caption cleveref xcolor float multirow tocloft parskip etoolbox index biblatex biber \
+ && tlmgr install latexmk listings caption cleveref xcolor float multirow tocloft parskip etoolbox index biblatex biber newtxtt \
  && cpanm JSON \
  && cpanm LaTeXML \
  && apt-get autoremove -qy make gcc curl wget git cpanminus libxml2-dev libxslt-dev \
diff --git a/.CI/latexml/Dockerfile.2.incremental b/.CI/latexml/Dockerfile.2.incremental
index 1b9d2664b..1dfe04bf8 100644
--- a/.CI/latexml/Dockerfile.2.incremental
+++ b/.CI/latexml/Dockerfile.2.incremental
@@ -1,5 +1,5 @@
 FROM modelicaspec/latexml:20201119
 
 RUN tlmgr update --self \
- && tlmgr install index biblatex biber \
+ && tlmgr install index biblatex biber newtxtt \
  && apt-get clean && rm -rf /var/lib/apt/lists/* /tmp/* /var/tmp/ /root/.cpanm/work*